[PR 91832] Do not ICE on negative offsets in ipa-sra

[PR 91832] Do not ICE on negative offsets in ipa-sra

Hi,

IPA-SRA asserts that an offset obtained from get_ref_base_and_extent
is non-negative (after it verifies it is based on a parameter).  That
assumption is invalid as the testcase shows.  One could probably also write a
testcase with defined behavior, but unless I see a reasonable one
where the transformation is really desirable, I'd like to just punt on
those cases.

Bootstrapped and tested on x86_64-linux.  OK for trunk?

Thanks,

Martin

2019-09-24  Martin Jambor  <mjambor@suse.cz>

	PR ipa/91832
	* ipa-sra.c (scan_expr_access): Check that offset is non-negative.

	testsuite/
	* gcc.dg/ipa/pr91832.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@276093 138bc75d-0d04-0410-961f-82ee72b054a4